IR: Add VariableInstruction.getASTVariable

Author: rdmarsh2

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll

@@ -612,6 +612,11 @@ class VariableInstruction extends Instruction {
   override string getImmediateString() { result = var.toString() }
 
   final IRVariable getIRVariable() { result = var }
+
+  /**
+   * Gets the AST variable that this instruction's IR variable refers to, if one exists.
+   */
+  final Language::Variable getASTVariable() { result = var.(IRUserVariable).getVariable() }
 }
 
 class FieldInstruction extends Instruction {

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll

@@ -612,6 +612,11 @@ class VariableInstruction extends Instruction {
   override string getImmediateString() { result = var.toString() }
 
   final IRVariable getIRVariable() { result = var }
+
+  /**
+   * Gets the AST variable that this instruction's IR variable refers to, if one exists.
+   */
+  final Language::Variable getASTVariable() { result = var.(IRUserVariable).getVariable() }
 }
 
 class FieldInstruction extends Instruction {

cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll

@@ -612,6 +612,11 @@ class VariableInstruction extends Instruction {
   override string getImmediateString() { result = var.toString() }
 
   final IRVariable getIRVariable() { result = var }
+
+  /**
+   * Gets the AST variable that this instruction's IR variable refers to, if one exists.
+   */
+  final Language::Variable getASTVariable() { result = var.(IRUserVariable).getVariable() }
 }
 
 class FieldInstruction extends Instruction {

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Instruction.qll

@@ -612,6 +612,11 @@ class VariableInstruction extends Instruction {
   override string getImmediateString() { result = var.toString() }
 
   final IRVariable getIRVariable() { result = var }
+
+  /**
+   * Gets the AST variable that this instruction's IR variable refers to, if one exists.
+   */
+  final Language::Variable getASTVariable() { result = var.(IRUserVariable).getVariable() }
 }
 
 class FieldInstruction extends Instruction {

csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Instruction.qll

@@ -612,6 +612,11 @@ class VariableInstruction extends Instruction {
   override string getImmediateString() { result = var.toString() }
 
   final IRVariable getIRVariable() { result = var }
+
+  /**
+   * Gets the AST variable that this instruction's IR variable refers to, if one exists.
+   */
+  final Language::Variable getASTVariable() { result = var.(IRUserVariable).getVariable() }
 }
 
 class FieldInstruction extends Instruction {